Looper mechanism or replacement unit for multiple needle lock stitch sewing machines



Aug. 7, 1951 G. A. BOETTCHER 2,563,639

LOOPER CHANISM OR REP EMENT UNIT FOR MULTIPLE EDLE; LOCK STIT SEWING MACHINES Filed Dec. 31, 1946 5 Sheets-Sheet l I INVENTOR: GUSTAV A. BOETTCHER Aug. 7, 1951 G. A. BOETTCHER 2,563,639

LOOPER MECHANISM OR R LACEME UNIT FO ULTIPLE NEEDLE LOCK S CH SE G MACHIN Filed Dec. 31: 1946 s Sheets-Sheet 2 INVENTOR: I GUSTAV A. BQETTCHER BY (KW/W6 ATTORNEY.

Patented Aug. 7, 1951 LOOPEB MECHANISM OR REPLACEMENT UNIT FOR MULTIPLE NEEDLE LOCK STITCH SEWING MACHINES Gustav A. Boettcher, Jackson Heights, N. Y.

Application December 31, 1946, Serial No. 719,480

9 Claims. I

This invention relates to means for producing double locked stitches without the use of shuttles and forming a two thread chain stitch seam while feeding all threads from original spools or bobbins without any rewinding'.

The main object of my invention is primarily to provide a double locked stitch replacement unit for multiple needle sewing machines-which is interchangeable so as to be capable of replacing the main operating portion or stitching unit with shuttles or bobbins of such a machine and thereby endowing the machine with new characteristics, or in other words, it is the object to change a double locked stitch multiple needle sewing machine employing shuttle bobbins to a lock stitch multiple needle sewing machine using loopers and continuous thread supply.

In such a unit, an upper needle thread and a lower looper thread together form a double locked stitch. By the double locked stitch is. meant a stitch produced, as mentioned, without a shuttle,

the upper needle thread and the lower looper thread being taken directly from large spools mounted on the machine involved, and by means of a looper, the lower thread is interlocked with the upper needle thread.

Another object of the invention is to provide a looper unit of such character that it provides ready accessibility of the operator to the loopers for threading the same.

A further object is to provide a unit of the mentioned character in which the looper holders are removable and capable of being locked in operative position, and in which the locking of the looper holders sets them accurately in place without adjustment.

Still another object is to simplify the manufacture as well as the structure and operation of multiple needle sewing machines, and to reduce the number of operating parts so that there will be fewer parts to get out of order.

A yet further object is to make the main oper ating portion of a multiple needle sewing machine more automatic than heretofore so that less skilled help will be required to run the same.

It is even an important object of the invention to so alter the construction of a multiple needle sewing machine that the machine will be far more free from vibration than such machines have been heretofore, and especially make it pos sible to greatly increase the speed of operation and thereby materially increase the output.

Other objects and the various advantages inherent in the invention and accruing from its application to actual practice will appear more 55 fully in detail as this specification proceeds.

In sewing machines using a plurality of needles for sewing or embroidering quilting and other fabrics, a certain amount of vibration has been assumed to be necessary and unavoidable, and likewise more or less frequent breakage of the threads. When in such a conventional machine, these threads break, the machine must be stopped and a bobbin holder removed for picking up the end of the broken thread or replacing the bobbin, or some other thread manipulation is required before the machine may again be started, all of which consumes time. Furthermore, the vibration and the sensitive condition of the threads limit the speed of operation of the machine and this directly limits the output of the same. Moreover, such limited speed of the ma chine when actually running is reduced insofar as output is concerned, when to this is added the delays occasioned by stoppages to repair broken threads.

In vieW of such familiar difficulties and disadvantages so far tolerated in the industry as unavoidable evils, I now propose to replace only a portion of a conventional lock stitch multiple needle machine with a self-contained unit, while using the remaining portions of the conventional machine in order to change it over to a double locked stitch multiple needle sewing machine. Of course, I may construct the entire machine according to the principles of my present invention without reference to any prior art lock stitch multiple needle sewing machine. By virtue of the features of my invention, several of the old problems of the prior art are completely bypassed and instead new advantages are introduced to the exclusion of above mentioned limitations and disadvantages.

In order to render the invention comprehensible in detail, the same is illustrated in the accompanying drawings forming part hereof, and

in which:

Fig. 1 is a perspective view of a multiple needle sewing machine made according to the principles of my invention and embodying the same in practical form, portions being broken away to better disclose certain details; the fabric rollers being also omitted;

Fig. 2 is a transverse section of the same machine as seen irom the left end of Fig. 1 when the left end frame is cut off, the cloth roller and Fig. i is a fragmentary end view or" a looperholder with certain adjacent portions in one position of operation;

Fig. is another view of the same in a second position of operation;

Fig. 6 is still another view showing a further step in the operation of the same looper holder; and

Fig. '7 shows the final step in the operation of said looper holder preparatory to returning to the position shown in Fig. 4.

Thorughout the views, the same reference numerals indicate the same or like parts.

As already indicated, the invention shown in the drawings is designed to eliminate many of the disadvantages of multiple needle sewing machines as heretofore constructed and in addition to eliminate the frequent stoppages and interruptions occasioned by thread breakages, as there are no bobbins to replace or similar lost motions necessary, due to the direct and simple construction involved.

Hence, in the practice of my invention, the machine has a bed I (Fig. 2), which may also have legs or supports in conventional manner (not shown), and supported upon this bed is a base plate 2 and a pair of opposite upright frame members 3, 3. As may be seen in Fig. 1, upon the frame members is a pair of bearings 4, 4 for a drive shaft 5 provided with an eccentric 6 at the near end operating the eccentric follower l and its rod 8, while at the other end the shaft has another eccentric 9 with an eccentric follower lfii with a rod ll, of which more later. Beyond the last mentioned eccentric, a drive pulley I2 is secured to the main shaft, having a belt l3 connecting the pulley to motor pulley M of a motor l5 whose base It is supported upon a portion of the bed or of the machine not shown, as the actual location of the motor is merely a matter of convenience.

The upper portions of the end frame members 3, 3 are connected together by a rear bridge member I! secured thereto by bolts or screws i8 (Fig. 2), and upon this bridge is fixed a series of brackets [9 (one shown), serving as guide supports for vertically movable needle bar guide rods and presser foot guide rods 2!. To the lower ends of the guide rods are secured the front needle bar 22 and rear needle bar 23, the bars being carried byneedle bar blocks 24 which are directly secured to the vertical rods 20, While needles 25 are fastened to the needle bars by screws 25, 26. The needle bar blocks, of which only one is shown for clarity in the drawings, are connected by a pin 2? to a link 28 which in turn is connected by a second pin 29 to, a bifurcated lever 35 fixed on a. rocker shaft 3! .passing through the previously mentioned brackets and extending into end bearings 32 (one shown) on end frames 3, 3. Upon the left end of this shaft is fixed crank lever 33 which is connected by a pin 34 to the upper end of the previously mentioned eccentric rod H, with the result that when, the motor drives the main shaft 5, eccentrio 9 will cause its follower Ill and rod II as well as the lever 33 to oscillate vertically and thereby rock shaft 3! and through lever and link 28 connectedthereto, also oscillate the block24 and needle bars 22 and 23 vertically for sewing with needles 25.

Upon the sides of end frames 3, 3 are secured two cloth roller arms 35 (one shown in Fig. 2),

held to the frames by screws or bolts 39 along their horizontal portions, while rearwardly these arms each is divided into two spaced arms 3', 4' separated :by a slot 40 for receiving the bearing blocks 4|, 42 of feed rollers 43, 44 and closed by an end strip 45 to prevent accidental removal of the rollers.

To the lower end of the vertical guide rods 2| is secured presser foot 46, having a clearance hole 47 for each needle, each rod having a collar 48 with a compression spring 49 above the same tending to urge the rod downwards by engaging against the upper portion of the guide block or bracket l9. The presser foot is depressed by cam operation derived from the movement of the main shaft by conventional means not shown, as the same forms no part of the invention and would only obscure the drawings.

Thus far, except for the base plate 2, the conventional portion of a multiple needle sewing machine has been described, but what follows may either be incorporated as part of the machine or made into an interchangeable unit capable of being made separately and after assembly installed as a replacement unit upon the bed 1 between end frame members 3, 3 and so con nected to the main shaft 5 that operation will occur when said shaft is driven by motor l5. Upon base plate 2 are mounted supporting brackets 50 (one shown) upon which are fastened a front long bar 5| and a corresponding rear bar 52, a series of spacer bridges 53, 53 being secured in spaced apart arrangement upon bars 5| and 52 and supporting needle plate 54 upon which the sewing is done, and in which there is a hole 55 for each needle. From the lower edge of each of the two bars just mentioned are fixed a limited group of bearings 56, 55, etc., through which the transversely slidable rods 51, 51, etc., extend and by which these rods are supported, said rods extendin through front supporting blocks 48, 48 and into rear supporting blocks 59, 5,9. The front blocks have each a plate secured thereon supporting a looper rod supporting bar 6 I, and the rear blocks 59 support a corresponding rear looper rod supporting bar 52 in a manner and for a purpose about to be explained.

The rear blocks 59 last mentioned are each forked with a slot 63 which is open downwards and occupied by a roller 64 mounted on a pin 65 in a double rocker lever 66 which in turn is fixed on the rocker shaft 61 in substantially upright position, the shaft being supported in bearings 58 on base plate 2. In the double or slotted rocker lever I 6'. is secured an adjustable block 69 connected to the rear end of eccentric rod 8 operatedv by eccentric 6 on main shaft 5, a pin l0 forming the connection between block 69 and the eccentric rod. 'The mentioned looper rod supporting or actuating bars 6| and 62, being supported themselves on blocks 58, 59 fixed on rods 51, '51 which are slidable in fixed bearings 56, 56, etc., are thus transversely oscillated through slotted blocks 59, levers 66 and shaft 61 with its lever I66, block 59 and pin 'HJ by eccentric rod 8 operated through follower 1 on eccentric 6 of main shaft 5.

'In order to release the looper rods or holders 12 for attending to broken threads on the individual loopers, and then return and lock these looper holders or carriers in position, the rear actuatin bar 62 has the slotted holes H through which looper holders i2, 12 are passed to extend through corresponding holes 13, 13 in front bar.

6|, however, as may best be seen in Figs. 2 and 3, upon the rear portions of the looper holders are rotatably mounted locking knobs 14, I4 prevented from dropping off the looper holders by nuts I5, and provided with oppositely projecting locking tongues or lugs I6, I6. Upon either side of each of the looper holders is a lock screw or stud 11 mounted on actuating bar 62 under the head of which stud or screw one of the locking lugs 16 of the locking knob adjacent thereto will frictionally engage when the looper holder carrying the knob involved is in place and the knob partly rotated on said looper holder. In Fig. 3, the looper holder at the extreme left has its locking knob disposed against rear-actuating bar 62 and turned into locked engagement of the lugs thereof with the immediately adjacent lock screws or studs 11, I1, locking this looper holder rigidly with said rear actuating bar 62 and causing the mentioned holder to follow the movements of this bar effected by rocker arms or levers 66, 56 and their shaft 61. As the front bar BI is also supported by rods 51 extending slidably through blocks 58 and strips or plates 60,

this bar likewise follows the movements of the levers B6 and shaft 61. Thus the slidable rods 51, the front and rear barsfil and 62 with blocks 58 and 59 and plates 6!] form a transversely oscillating system for oscillating the looper holders, as will be further set forth.

The second looper holder from the left in said Fig. 3 has the knob 14 thereof turned sufficiently to release the holder and allow the same to be rearwardly withdrawn at will into the position occupied by the third looper holder from the left for rethreading when a thread has broken. The slotted holes H serve a further purpose, namely to allow complete withdrawal of the looper holders if desired. On each of the looper holders is mounted at least one looper 18 having a forwardly directed slot I9 and two thread holes 80, 8]; there being two such loopers mounted upon a plate 82 fixed directly upon each looper holder and serving to hold the loopers in elevated positions above each holder or carrier and thereby facilitate sliding of said plate 82 through the upper slotted portions of the slotted holes or apertures 'Il. When the looper holder is to be entirely withdrawn as far as it will go, the first step is, of course, to turn knob I4 thereon sufficiently to free its lugs 16 from the two adjacent screws or studs 11, after which it is slidout of the hole I3 in the front looper holder support bar 6| and then drawn further rearwardly while guiding plate 82 supporting the loopers through the slotted portion of slotted hole II in rear looper holder support bar 62. In such withdrawn position the loopers become quite readily accessible at the rear for threading and cleaning,etc..;

However, independently of the locking and rein a long rail or rocking bar 88 in which are a series of holes spaced apart as shown at 89, 89, etc. Into these holes project individual pins90" secured upon the lower ends of looper holder rocker arms 9| secured upon each looper holder at the upper ends thereof. The rail or rocking bar 88 is capable of being longitudinally oscillated to a limited extent while resting on the lower rollers 85 engaging in lower slots 81, the upper rollers 84 engaging in slots 86 and thereby confining the rail in place but allowing the mentioned longitudinal movement. In order to thus oscillate the rail, a forwardly projecting pin 92 fits slidably in the box cam slot 93 on cam 9 fixed on main drive shaft 5, this slot or track shifting the pin periodically and thereby shifting the rocking bar or rail lengthwise and thereby also shifting pins 90 on arms 9| and slightly rock the looper holders in their holes or mount-- leasing features just described, the loopers are intended to have two movements, the transverse oscillation already described by the sliding movement of the system including front and rear ings H, I3 in bars 62, 6|, respectively. The rocking movement just mentioned is co-ordinated with the transverse oscillation or sliding movement of the looper system and the vertical movement of the needles on the needle bars already described. The result is that the needle in each case will descend at one side of the respectively adjacent looper, as shown in Fig. 4, when the movement of the eccentric rod 8 due to the rotation of eccentric 6 with main shaft 5 will rock shaft 6'! and levers or arms 66 from their position shown in Fig. 2 to approximately the position shown in Fig. 3. This will draw the looper rearwardly so that the needle in each case is beyond the forward end of the looper, at which moment the cam slot 93 of cam 94 shifts pin 92 of rocker bar or rail 88 and thereby also the latter rail and the looper holder pins 90. Thus the loopers will be rocked from the position shown in Figs. 4 and 5 to the position shown in Figs. 6 and '7, the needle remaining down during the shift from the position of the loopers in Fig. 5 to that of Fig. 6, after which the needle will be raised as shown in Fig. '7. Subsequently, the needles will be held in the raised position while the loopers are again rocked back to the original position of Fig. 4, when the cycle willbe repeated.

The upper thread 95 (Fig. 2) comes from a thread supply, (not shown) to hole 96 in tension bar 9'! supported by brackets 98 fixed on brackets l9, and passing through the tension stud structure 99 proceeds to hole or thread eye H10 in thread guide bar lfll supported by angles I02 mounted on the same brackets IS. The thread then passes upward to eye I03 in thread take up bar I64 fixed to the forwardly projecting short bar I05 secured to each of the needle bar guide rods 20 and thence passes down through the eye of the particular needle involved and is car ried by the needle through the cloth IE6 resting on needle plate 54 and the needle hole 55 therein.

The lower thread I I11 is brought from a thread supply (not shown) to one of a series of tension stud structures I08 (Fig. 2) on rear tension bar H19 secured to the rear lower portions of end frames 3, 3, after which the thread passes through eye H0 to lower take up bar Ill fixed on block 59 and up to rear thread guide bar. I I2 supported by brackets H3 on frame members 3, 3. The thread passes into eye I I4 in bar I I2 and thence beneath needle plate 54 to rear eye H5 in looper I8 and finally through front eye H6 in the same looper, at which .point the thread engages with upper thread 95 from needle 25. As the sewing proceeds, the loopers are. rocked r horizontally with partial rotation of looper hold- .ers 12 in co-operation with the vertical movement of the needles and the transverse oscillation of the entire looper system as already described, with the result that the threads are concatenated into lock chain stitches in the cloth 1.96 as it is drawn by the feed rollers 43, 44 from supply roller 38 up over apron I I! secured to the spacer bridges 53 and over needle plate 54. The feed rollers are connected by appropriate gearing to main shaft in more or less conventional :manner (not shown). The rocking of the loopers concatenates the upper thread from each needle with the corresponding lower thread from the looper below to produce the mentioned lock chain stitches in quick succession. In fact, the parts are relatively light when compared with conventional structures for similar purposes and are capable of running at far greater speeds than heretofore possible in multiple needle sewing machines.

When a thread breaks, which rarely occurs, it is but necessary, after stopping the machine, to partly turn the lockingknob of the looper holder involved to free the lugs of the knob from the locking screws or studs beside said knob on the rear actuating bar, whenit is a simple matter to .pull the looper holder far to the rear so that the loopers thereon are freely accessible behind the needle plate for rethreading said loopers. Then the holder may again be pushed forward to stop the knob against rear bar 62 and the knob partly returned to engage the lugs 16 thereof with the locking screws H, when it will be found that the loopers have been accurately restored to original position without special car or thought being necessary to effect such accurate replacement.

While the main operative portions of the machine have been described as mounted or supported upon the base plate 2, so that it substantially carries these portions to form a replacement unit therewith which ma be installed upon bed I as such between end frames 3, '3, it is, of course possible to mount and support said por-' tions directly upon bed I without plate 2 if it is desired to build upthe whole machine in that manner. However, as man multiple needle sewing machines already exist, they may be radically reconstructed. by replacin the main operative portions thereof with the above described operative replacement unit.

Manifestly variations in the form or number of the parts making up the unit portion of the machine vembodying the invention, and other alterations which do not radically depart from the principles involved in said invention, may be resorted to, and even parts may be used without others and the unit may be installed on any desired type of multiple needle sewing machine and may be used to sew various kinds of desired stitches, Within the scope of the invention.

Having now fully described my invention, I claim: I

l. A multiple needle sewing machine, comprising a fabric support, means for passing a fabric to be sewed over the support, a movable means provided With sewing needles, drive means for operating the movable means to cause the needles to penetrate the fabric and the fabric support, bearing means rigidly associated with the latter, an oscillating member movably supported by said bearing means, a plurality of looper carriers shiftably mounted on the oscillating member and individually supporting a thread carrying looper for each needle beneath said .fabric support, locking means for locking the looper :carriers rigidly to the oscillating member formoving the looper .carriers positively with said oscillating member, the loopers on the looper carriers causin the threads thereof to be concatenated with the threads of the needles during the sew- .ing operation to produce chain stitches in the fabric resting on said fabric support, means for communicating movement from the drive means to said oscillating member to cause the same and the loopers to oscillate along one direction to coo erate with said needles during the sewing operation by effecting loop taking movements, and furthermeans communicating with said drive'means to bedriven thereby effective to move the loopers along a second direction substantially at right angles .to said one direction to further co-operate with said needles during said sewing operation to effect needle avoiding movements and thus form the stitches in said .fabric.

2. In a multiple needle sewin machine having a support, a needle bar carrying a plurality :of thread carrying needles, means for movably supporting saidneedle bar on said support and drive means for moving said needle bar to cause the needles to penetrate a fabric, the combination of a fabric support mounted in stationary association with said first mentioned support, bearing means fixed upon said fabric support, a looper holder or carrier frame having portions movably engaging with said bearing means and guided thereby to move alon one direction, at least one looper holder shiftably mounted upon said frame and having a thread carrying looper thereon normally disposed beneath said fabric support, looking means upon the looper holder having means for engaging aportion upon said framein locking engagement to retain the looper holder :in .rigid relation with said frame for positive operative movement therewith, means movably supported upon aforesaid support and connected to said looper holder for moving the latter in a second direction substantially at right angles with the one direction and thereby cause said loopers to perform an operative cycle of movement including loop taking and needle avoiding movements, said last means being connected to said drive means for deriving movement therefrom, and means for timing the operative movement of the looper holder frame with respect to the movement thereof in the second direction and the movements of the needle bar during operation.

3. A multiple needle sewing machine according to claim 2, in which the looper holder frame has a plurality of sliding rods extendin through the bearing means and the means for moving the frame in the second direction comprise a shiftable member movably mounted upon the first support, means upon the drive means communicating the movement of the latter thereto for shifting said shiftable member, and means communicating the movement of said shiftable member to said looper holder frame.

4. A multiple needle sewing machine according to claim 2, in which the looper holder is elongated and longitudinally shiftable and the looking means includes a rotatable knob having a lug thereon and a screw or stud on the fram engaged by said lug for retaining the looper holder in fixed position in the longitudinal direction of said looper holder.

5. A multiple needle sewing machine according to claim 2, in which the looper holder frame has two substantially parallel bars disposed lengthwise of the first mentioned support, one of the bars having a plurality of holes or apertures extending transversely therethrough and the other bar is also pierced by corresponding holes, and the looper holders fit slidably in the holes or apertures in both bars transversely of the latter, and in which the locking means includes at least one screw or stud member upon one bar adjacent to each holder and a rotatable knob on each looper holder havin a lug for engaging in looking engagement with said screw or stud upon partial rotation of said knob when the same is disposed in predetermined relation to said one bar.

6. A multiple needle sewing machine according to claim 2, in which the looper holder frame has two substantially parallel bars for supporting the looper holders, one bar having a plurality of holes or apertures extending transversely therethrough and the other havin a corresponding plurality of slotted holes or apertures extending transversely therethrough, and the looper holders are each slidably supported in one hole or aperture in the one bar and the corresponding slotted hole or aperture in the other bar and has a looper support thereon carrying at least one looper, the looper holder in each case being capable of sliding longitudinally in the holes in which it is located and also sliding with the looper support through the slotted hole for giving access to said looper outside the fabric support at will.

7. A multiple needle sewin machine accord ing to claim 2, in which the drive means includes a driven shaft upon the support carrying an eccentric having a follower with a rod thereon, a second shaft also supported upon said support and having a lever connected to the looper holder frame for moving the latter, and a further lever on said second shaft connected to the rod upon the follower to transmit movement from the latter to said second shaft.

8. A multiple needle sewing machine according to claim 2, in which the looper holder frame has a pair of bars spaced apart and pierced by corresponding series of holes for receiving looper holders slidably therein transversely of said bars, and the locking means on each looper holder includes a manually adjustable member adapted in one position of adjustment to engage in lookin engagement with a portion of one of said two bars, and in which the movably supported means for imparting the second direction movement to looper holders includes an arm upon each having a projection upon one portion thereof, an elongated member movably supported upon the first support, and means including apertured portions upon said elongated member into which the projections upon said arms extend, said elongated member being longitudinally movable by the drive means for rocking said arms and partly rotating or rocking said looper holders in the holes in said. bars and thereby rocking the loopers on said holders for co-operation with th needles durin the sewing operation.

9. An operating unit for a multiple needle sewing machine having a drive shaft and a needle bar with needles thereon movable by said drive shaft upon rotation thereof, said unit including a bearing support mounted on said machine hav= ing bearings spaced apart and surmounted by a needle plate for supporting a fabric during sewing, a plurality of supporting rods slidably mounted in said bearings beneath said needle plate, a front bar mounted upon said rods and a rear bar also mounted on the same rods, said rods and bars forming a movable looper holder supporting unit, a second shaft mounted for partial rotation upon said support having a lever upon one portion, a driving member upon the drive shaft connected to the lever for rocking the second shaft, a second lever on said second shaft projecting into a slotted portion upon one of said bars to slide said unit in said supporting bearings, a longitudinally movable bar supported upon said first support, means upon the drive shaft for reciprocating said last mentioned bar, looper holders supported slidably in corresponding holes in the front and rear bars, said looper holders being disposed transversely with respect to the front and rear bars as well as the longitudinally movable bar, arms fixed upon the looper holders havin projections extending into apertures in the last mentioned bar so as to rock or partly rotate said holders in situ upon reciprocation of said bar by rotation of the drive shaft, and locking means: upon the looper holders for preventing the latter from sliding in the holes in the front and rear bars, said lockingmeans being manually releasable to allow the looper holders to be partly withdrawn from beneath the needle plate to expose looper portions thereon for threading the same at will.

GUSTAV A. BOETTCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,802,869 Boettcher Apr. 28, 1931 1,948,876 Boettcher Feb. 27, 1934 2,400,528 Behrens May 21, 1946 

